Automatic transmission



Jan. 7, 1941. KRQME 2,228,082

AUTOMATIC TRANSMISSION Filed Oct. 5, 1958 5 Sheets-Sheet 1 .E'owneo F: 118005.

' Jan. 7, 1941. E. F. KROME AUTOMATIC TRANSMISSION Filed Oct. 3, 1938 5 Sheets-Sheet 3 .Z'owneo Ffieons.

.E ZQ

E. F. KRdME 2,228,082

AUTOMATIC TRANSMISSION Filed 001'.- 3, 1938 5 Sheets-Sheet 4 Jan. 1, 1941.

II IIIIIIIIIIIIIII Jan. 7, 1941. E. F. KROME AUTOMATIC TRANSMISSION Filed 001;. 5. 1938 5 Sheets-Sheet 5 Patented Jan. 7, 1941 UNITED STATES PATENT OFFICE AUTOMATIC TRANSIVIISSION 2 Edward F. Krome, Chicago, Ill. Application October 3, 1938, Serial No. 233,127 16 Glailns. (01. 192-35) This invention relates to automatic transmissions and more particularlyto automatic transmissions including a conventional. clutch and gear box, .or other forms of disengageable torque transmitting mechanism and speed changing elements having definite stepped ratios.

- One of the principal objects of this invention is to provide an automatic control mechanism which is adapted to be combined with a conventional clutch and gear box, and to form there-- with an automatic transmission.

Another object of this invention is to provide an I automatic transmission control mechanism for combination with a conventional clutch and gear box which will automatically cause a disengage-- ment of the clutch and a change in the ratio provided by the gear box followed by a re-engagement of the clutch whenever the conditions under which the vehicle is being operated make a change in ratio desirable and when, at the. same time, the operator of the vehicle releases the accelerator and momentarily allows the torque' being transmitted by the engine to drop to zero. Another object of this invention is to provide an automatic transmission control mechanism which operates upon the release of the accelerato'r of the motor vehicle by the operator, and

which will completely execute a disengagement of the clutch, a gear shift and a re-engagement of the clutch in the proper order no matter how 'momentary' may be the release ofthe pressure p upon the accelerator.

Another object of this invention is to provide an automatic transmission control mechanism in which the shifting from one speed to the next takes place only upon the release of the accelerator pedal and in'which the determination of whether a shift to a higher speed is to be made or not is controlled by the speed of thevehicle.

Another object of this/invention is to provide an automatic transmission control mechanism of the, general character described above and in which means are provided to prevent the making of a shift from low speed to high speed withoutpassing through intermediate speeds in cases where the operator of the vehicle has accelerated in low speed to a vehicle speed at which a shift into high would normally occur.

Another object of this invention is-to provide anautomatic transmission control mechanism for use with a motor vehicle having a clutch and a gear box and in which means are provided for automatically disengaging and ire-engaging the clutch, the speed of re-engagement being automatically determined by the selection of a gear ratio in the gear box.

Another object of this invention is to provide a power gear shifting device operated by suction from an engine manifold, the suction being used I to place-a liquid under pressure and the liquid v ticularity in the appended claims.

under pressure being employed in small cylinders mounted uponthe gear box in order to performthe actual shifting;

Another object of this invention is to provide a small and compact hydraulic gear shifting and manner of construction, together with .fur-

ther objects and advantages thereof, may best be understood by reference to the following description, taken in connection with the accompanying drawings, in which:

Figure 1 is a diagrammatic view of the greater part of one of the preferred embodiments of the invention;

Figure 2 is aidiagrammatic view of the remainder of the embodiment of the invention shown in Figure -1;

Figure'3 is a diagrammatic view of a portion of the invention shown in Figure 2, the parts being in a different position;

Figure 4-is a diagrammatic view of the same portion of the invention as shown in Figure 3,

the parts'being in still another position;

Figure 5 is a diagrammatic view on an. enlargedscale of one form of speed selector valve;

Figure 6 is a diagrammatic scale of one form of hand control valve by means of which the automatic mechanism is set in "ahead position, "reversef position,'or neutral;

Figure 7 is. a diagrammatic view of one form of one ofthe clutch controlvalves;

Figure 8 is a cross-sectional view of one of the preferred forms of the main clutch valve and the clutch engagement control;

Figure 9 is a cross-sectional view of one of the preferred forms of master valve controlled by the accelerator pedal;

view on an enlarged Figure 10 is a plan view of one of the preferred forms of the part of the invention which is shifting of the gears;

Figure 11 isa cross-sectional view taken on the Figure 12 .is a horizontal sectional view mounted upon the gear box and does the actual through one of the cylinders and the assoqated valve of the portion of the mechanism shown in Figure 10'.

General description which are interconnected with each other and provided with auxiliary mechanisms in order to form a complete automatic transmission control system. In brief, the invention comprises a hy-' draulically operated shifter l5 which is adapted to be placed on a conventional gear box or transmission and to engage and shift the gears therein. The shifter I5 is supplied with oil or other hydraulic fluid under pressure by means of a direct acting vacuum powered pump l5 which is supplied with vacuum and caused to operate whenever the clutch pedal I1 is depressed. Which speed the gear box will be shifted into'by the shifter |5 when the pump I5 is actuated is determined by a group of vacuum operated relay valves l8, I9, 20 and 2 I. Each of the relay valves l8, I9, 20 and 2| controls theshifting into one of the four speeds, reverse, low, intermediate, and high, and whether the reverse relay valve I8 is actuated or one of the forward relay valves I9, 25 and 2| is determined by the position of a hand control valve 24 which may be set in either ahead, reverse or neutral position.

Which of the ahead relay valves I9, 23 and 2| is to be operated at anytime is determined by the position of an automatic selector valve 25 which is moved to the positions corresponding to the various forward speeds by meansof a centrifugal governor 28 (shown in Figure 2) which is connected to rotate at a speed proportional to the speed of the vehicle. The governor 25 controls the automatic selector valve 25 through aratchet and pawl mechanism 21 which prevents the selector valve 25 from being moved directly from first speed to third speed without stopping in the second or intermediate speed position until a shift into intermediate speed has been made. The movement of the clutch pedal i1 is controlled directly by a clutch relay valve 28 which is combined with an automatic Vent control 38 which provides different rates of engagement of the clutch according to the speed which has been selected by the hand controlled valve 24 and the automatic selector valve 25. The clutch relay valve 28, in turngis controlled from a master valve 29 which operates whenever the accelerator 3| is entirely released by the driver of the vehicle. In order to prevent unnecessary actuation of the clutch pedal II, a lockout valve 32 is provided to prevent actuation of the clutch relay valve 28 except when the automatic selector valve 25 is in a position to cause a gear shift. The automatic selector valve 25 and lockout valve 32 are so arranged that they can move to a position beyond that corresponding to third speedafter the gears have been shifted into third speed, and

in this position the lockout-valve 32 prevents the clutch relay valve 28 from operating.

As mentioned above, the shifter l5 operates when it is supplied with liquid under pressure from the pump l5 which, in turn, is controlled by the depression of the clutch pedal H, the clutch pedal I! being, in its turn, controlled by the master valve 29. In order to prevent the clutch pedal I I from being allowed to rise and cause engagement of the clutch before the shifter l5 has completed a shift, an interlocked mechanism is provided to hold the master valve 29 open until the completion of a shift. The details of this interlocked mechanism are described below.

The shifter The shifter l5, which is shown in detail in Figures and 11, comprises an octagonal frame 31 which is adapted to be secured to the top of a conventional gear-box or transmission. The particular means used for securing the shifter in place are not shown as they form no part of the present invention and will differ for each type of gear box. The frame 31 carries a pair of paral lel guides or slideways 38 extending horizontally from one end of the frame to the other. A slide 39 is mounted between the guides 38 and is provided with portions 4| which embrace the guides 38 and restrict the slide 39 to movement longitudinally of the guides 38.

The slide 39 carries within it a block 42 mounted so as to be able to slide laterally. The block 42 carries a pin or stud 43 which projects down out through an aperture 44 in the bottom of the slide 39. The pin 43 performs the same function in the gear box-as the lower end of the gear shift lever in a conventional manually operated transmission, and is adapted to engage the shifting elements 45 in the same way as a conventional gear shift lever. The pin 43 is therefore provided with means to move it along the H-shaped path shown in Figure 10.

Movement along the longitudinal sides of the H is accomplished by moving the slide 39 along the guides 38. A pair of cylinders 45 and 41 are secured to the frame 31 at each end of the guides 38 and are provided with pistons and with piston rods 48 and 49 whichbear against the ends of the slide 39. Thus, the admission of oil or other hydraulic fluid to one of the two cylinders 45 and 41 will move the slide 39 and the block 42 and pin 43- carried thereby longitudinally'in one direction and the admissiorfof oil or hydraulic fluid to the other cylinder will movethe slide 39, block 42 and pin 43 in the other direction.

Lateral movement of the pin 43 and the block 42 which carries it is accomplished by means of a pair of side cylinders 5| and 52 secured to the I pin 43 extends, the pin being a close fit in the aperture. Thus, when oil under pressure is admitted to one cylinder 5| or the other 52 at the sides of the shifter, the outer shell 53, 54 will be moved to one side or the other and will carry the pin 43 and laterally sliding block 42 with it. Thus the'pin 43 can be moved from one side to the other of its H-shaped path.

Although means might be provided for admitting pressure to the various cylinders only when they were called upon to cause movement of the pin 43, I have found that no inconvenience is caused by simultaneously admitting pressure to one end cylinder and one side cylinder and that the construction of the device can be materially simplified by causing it to operate in this manner. For example, if a shift is to be made from reverse to first, the oil or other liquid under pressure is admitted simultaneously to the rear end cylinder 41 and the left side cylinder 5| and the piston rod 49 move-r the slide 39 forward while the piston rod 48 in the side cylinder 5| holds the outer shell, 53, 54 over to the right and keeps the pin or stud 53 on one leg of its H shaped path so that it moves from reverse position to first speed position. If a shift is to be made from first speed to second speed, liquid under pressure is admitted to the front cylinder 45 and the right side cylinder 52.

During the first portion of this shift, the cylinder 52 urges thepin. 43 sideways toward the other side of its H-shaped path but does not move it because the pin 43 is kept from moving from one side'to the other of its H-shaped path except at the center by the shifting elements 45, which it engages, in the same way as a conventional gear shift lever is kept from moving from one side of its H-shaped path to the other except at the center.

Thus, during the first part of the shift from first to second, no lateral movement takes place and the slide 39 and the block 42, pin 43 and outer shell 53, 54 are moved longitudinally by the piston rod 48 of the forward cylinder 46. When these reach the middle of the guides 38, the pin 43 is free to move sideways and the side cylinder 52,

which already contains oil under pressure, im-

mediately acts through the piston rod 50 to move the outer shell 53, 54 and the pin 43 over to the other side of the H-shaped path. During this lateral movement, the pin 43 is prevented from moving longitudinally. by the shifting elements 45 in the same way as an ordinary gear shift lever is prevented from moving longitudinally while it is being swung from one side to the other of its H-shaped path, and the piston rod 48 of the end cylinder 46 is stationary. As soon, however, as the side piston rod 56 has completed its movement and the pin 43 has reached the other side of its H-shaped path, the piston rod 48 of the end cylinder 46 resumes its movement and pushes the slide 39 and pin 43 to the ends of their paths, thus completing the shift from first speed to second speed. The other shifts are made in a to the shifter. The oil pressure line 55 through similar manner. Thus each of the shifts to the four different speeds requires the admission of oil under pressure to two of the four cylinders 46, 41, 5| and 52, a different pair of cylinders being utilized for shifting to each speed.

The connections for supplying oil under ,pres-, sure to the four cylinders 46,41, 5| and 52 are arranged so that it is necessary to have only four oil lines or conduits 55, 56, 51 and 68 leading which oil is supplied to cause the shifter to move into reverse position, for example, is connected to both the left side cylinder 5| and the forward ended cylinder 46, as shown in Figures 1 and 10, sothat oil supplied through this line will cause the shifting pin 43 to move into the reverse position.- Similarly each of the other oillines, 56,

51 and 58 are connected to one of the endicylinders 46 and 41 and to one of the side cylinders 5| and 52.

It will be noted that each of the four cylinders 46, 41, 5| and 52 can be supplied, with oil under pressure through two of the four lines 55, 56, 51 and 58 and that means must be provided to prevent the oil supplied through one line leading to a cylinder from escaping through the other line leading to that same cylinder. For this purpose, each of the cylinders is provided with an I automatic valve. Since the four automatic valves in the four cylinders are similarto each other, it will be suficient to describe only the one associated with the forward end cylinder 46.

The head of the cylinder 46 is provided with a transverse cylindrical valve chamber 6| which communicates with the interior of the cylinder through a port 62. Each end of the valve chamher 6| is closed by a valve seat 63 which is screwed into place and which is provided with a central passage 64. The top of'each valve seat 63 is provided with an upstanding cylindrical wall 65 which surrounds the opening to the central pasment 45 on the right:

sage 64. A cylindrical valve plunger 66 is slidably mounted in the valve cylinder 6| and its ends are provided with annular recesses 61 adapted to receive the upstanding-cylindrical walls 65 on the valve seats 63. The two oil lines 55'and 51 through which oil is supplied to the cylinder 46 for performing the two shifts in which this cylinder is employed are connected to the two central passages 64 in the two valve seats 63.by means of intermediate oil lines 68 and 69. Thus, when oil under pressure is supplied to the cylinder 46 through either of the oil lines 68 or 69, the valve plunger 66 is forced by the pressure of the incoming oil against the v'alveseat 63 opposite the valve seat 63 through which the oil is entering. Thus the valve seat 63 through which oil is not being supplied is sealed off by the plunger 66 and the escape of oil therethrough is prevented.

While any conventional or suitable means may be employed for interlocking the shifting elements 45 so that only one of them may move at a time,

which is pivoted a shoe 14 which extends in hori-.

zontally toward the center of the shifter. A spring 15 is provided to press the pawl 1| down and to simultaneously hold the shoe 14v up against the bottom of the side cylinder 5| or 52 immediaately above it. The side cylinder 5| or 52 thus forms a guide'for the shoe 14 and keeps itapproximately horizontal as it is moved toward or away from'the center of the shifter. Each shoe 14 is placed so that its edge will ride against the side of the laterally movable outer shell 53, 54 carried on the slide 39. Thus, when the outer shell 53, 54 is moved over toone side or the other by one of the cylinders 5| or 52 and moves the pin 43 into engagement with one of the shifting elements 45, the side of the shell 53, 54 will bear against one of the shoes 14 and move it sideways, thereby causing the pawl 1| associated with it to rise out of engagement with the shifting element 45. As shown in Figurell, the

shell 53, 54 has been moved to the right by the action of the oil admitted to the cylinder 5| on the left, and the shoe 14 on the right has been moved laterally and has raised the pawl 1| associated with it out of engagement with the shifting ele- At the same time, the laterally movable outer shell, 53, 54 has moved out of engagement with the shoe 14 on the left, allowing the spring 15 to move the pawl 1| on the left down into engagement with the left-hand shifting element 45, thereby looking it in neutral position.

The vacuum operated hydraulic pump and its I connections pump cylinder 8| contains a pump piston 83 which is directly connected by a piston rod 84 to a piston 85 in the vacuum cylinder 82.

The vacuum piston 85 is forced up .by connecting the end of the cylinder 82 above the piston to a source of vacuum through a conduit 86, the atmosphere being allowed to act on the underside of the piston 85 through a vent 81 in the bottom of the cylinder 82. The return of the piston 85 to its lower position after the vacuum is cut off and atmospheric air allowed to return to the cylinder above the'plston is accomplished by means of a weight 88 carried by the piston.

The upper part of the pump cylinder 8| is connected to a reservoir 88 through a spring loaded inlet valve 8| Thus, when the vacuum piston 85 is moved down by the weight 88 and carries the pump piston 83 down with it, liquid will be drawn through the valve 8| from the reservoir 88 to the pump cylinder 8|. When the pump piston 83 is forced up by the admission of vacuum 'to the vacuum cylinder 82, the liquid in the pump cylinder 8| will be forced out through a spring loaded outlet valve 82 into an oil pressure conduit 83 leading to the four relay valves l8, I8, 20 and 2|.

Relay valves The four relay valves I8, I8, 28 and 2| serve to determine to which of the four conduits 55, 58, 51 and 58 liquid under pressure will be delivered by the operation of the pump I8. The four valves I8, I8, 28 and 2| are all alike, so a description of the construction and operation of one of them will serve to explain them all. Y The first of the four relay valves is the reverse valve I8. It comprises a cylinder having three ports spaced along its length. The upper port is connected to a branch of the oil pressure supply line 83 leading from the pump I8. The central port is connected to the reverse oil line or conduit through which oil under pressure is sup plied to the shifter |5 when it is desired to shift into reverse. The third or lower port is connected to a branch of an oil return line 84 which leads to the oil reservoir 88 to which the pump inlet valve 8| is connected. The cylinder of the valve I8 contains a dumbbell-shaped piston 85 whose two ends fit closely in the cylinder and whose central portion or waist provides a space between the two ends across which oil can flow. The bottom of the valve I8 is open'and is provided with a spring 88 connected to the valve piston 85 to hold it in its lower position. When the valve piston 85 is in this position, the branch of the oil supply line 83 leading to the valve I8 is closed by the upper end of .the valve piston 85 while the reverse oil line or conduit 55 and the oil-return line 84 open into the space around the waist of the piston 85 and are thus in communication with each other.

The valve piston 85 israised to its upper position by connecting the top of the cylinder of the valve I8 to a source of vacuum through the conduit 91. When the piston 85 is in its upper position, its lower portion covers the lower port and closes the branch of the oil-return conduit 84 leading to the oil reservoir 88. At the same time, the upper port is uncovered, thus placing the branch of the oil pressure supply line 83 leading to the valve I8 in communication with the reverse oil line-or conduit 55. Thus, when the reverse valve piston 85 is in its upper position and the oil pump I6 operates, oil under pressure will be forced through the oil pressure conduit 83, the reverse relay valve I8 and the reverse oil line 55 to the shifter I5. As will be explained in greater detail below, the means for applying vacuum to the upper ends of the relay valves I8, I8, 28 and 2| are arranged so that vacuum is applied to only one valve at a time. Thus, when the piston of one of the relay valves, such as the reverse valve I8, is in its upper position, the pistons of the other three relay valves will be in their lower position. Thus, while one of the four oil lines leading to the shifter I5, such as the reverse oil line 55. will be placed in communication with the oil pressure supply line 83 so as to receive oil under pressure from the pump I6, the other three oil lines 58, 51 and 58 leading to the shifter I5 will be in communication with the oil-return line 84 leading to the oil reservoir 88. The connection thus provided to the oil reservoir 88 is necessary because when, for example, oil is admitted to the forward end cylinder 48 of the shifter and forces the piston and piston rod 48 out of that cylinder, the piston and piston rod 48 in the opposite end cylinder 41 will be forced in, forcing the oil out of that cylinder. The oil thus forced out of the cylinder 41 will return to the oil-return line 84 and oil reservoir 88 through one or the other of the two oil supply lines 58 and 58 through which oil may be supplied to it. Through which of the two lines 56 and 58 the oil is returned depends upon the position in which the automatic valve associated with the cylinder 41 happens to be. When it is in the position shown in Figure 1, the oil will return through the first speed oil line 58 and through the first speed relay valve I8. Thus a passage is always provided for the return of oil to the oil-retum line 84 and oil reservoir 88 from which ever ones of the four cylinders. 41, 5| and 52 of the shifter I5 happen to be opposite the cylinders which are being employed in making a shift.

From the above description, it will be apparent that, if a shift is to be made, the speed to which the shift ismade is determined by which 'of the four relay valves I8, I8, 28 and 2I has its upper end connected to a source of vacuum so as to lift the piston within it, and it will also be apparent thatthe time at which the shift for which the selector valves are set is determined by when the vacuum cylinder 82 on the pump I5 is con nected to a source of vacuum.

M aster 2201128 The connection of the pump I8 and the relay ture I88, I88. The aperture III in the up, er seatleads directly to the atmosphere, and in addition to serving as a vent, provides a passage for a valve stem I84. The valve stem I84 is secured at its lower end to a piston I85 within the cylinder, the piston I85 being provided with annular grooves I88, I81 at each end adapted to receive the upstanding annular walls of the valve seats I82, I83. Thus, when the piston I85 is at either end of the cylinder I8I, orie of the grooves I88 and I81 c0- is connected to a conduit I29 through which the operates with the valve seat I02 or I03 at that end of the cylinder to form a seal similar to a labyrinth packing, thus effectively preventing leakage.

The aperture I09 in the lower valve seat I03 is at the end of a short tube III concentric with the valve cylinder I| and piston I06 and having its lower end closed by a cap H2. The tube III contains a helical spring II 3 whose lower end ,is secured to the cap 2 at the bottom of the tube and whose upper end extends through the aperture I09 in the valve seat I03 and is secured to the end of the valve stem I04 projecting through the valve piston. The spring I I3 is under tension so that it normally holds the piston I05 down on the lower seat I03, thus sealing off the upper end of the tube III.

One side of the tube III is provided with a connection I I4 which, as shown in Figure 1, leads to the intake manifoldv II5 of the engine l|0 of the vehicle on which the automatic transmission control mechanism is used, the suction in the intake manifold being the source of power for operating the entire mechanism. Thus, when the valve piston I05 is held down on the lower seat I03 by the spring II3, the vacuum in the connection II4 to the engine manifold 5 is sealed off from the valve cylinder IN, and the valve cylinder IN is in communication with the atmosphere through the aperture I 08 in the upper seat I02. When the valve piston I05 is raised against the upper seat I02 by the valve stem I04, the opening I08 to the atmosphere will be sealed and the interior of the cylinder IOI will be connected to the source of'vacuum through the opening I09 inthe lower valve seat I03. The interior of the valve cylinder IOI will thus be under vacuum or vented to the atmosphere according to whether the valve stem I04 is liftedup or allowed to be pulled down by the spring II3 'conder I0 I is communicated to the other elements of the transmission control mechanism through a port 1 in the side of the cylinder MI.

'The stem I04 of the master valve 29 is raised, when the accelerator pedal 3| is entirely released, by means of a lever II8 connected to the valve stemand a link 9 connecting the lever I I8 to the accelerator 3|. The link H9 is provided with a lost motion connection |2I- so that the accelerator 3! can be fully depressed without carrying the link II9 'with it and yet will cause the link I I9 to move in the direction to open the master valve 29 when .the accelerator is fully released. The accelerator is connected by a conventional linkage I22 to the throttle I23 or other fuel control device on the engine H6 and is provided with a spring I24 to cause it .to rise in the conventional manner when released. The spring I24 is, of course, strong enough to easily over come the spring H3 in the master valve, since the latter need only bestrong enough to overcome friction in the valve and its operating linkage.

Besides the linkage H0 and H9 connected to the accelerator 3| by which the master valve 29 is opened and held open, a second means is provided for holding it in open position. This second means comprises a small motor cylinder I21 directly above and concentric with the main part of the master valve 29. The valve stem I04 extends past its connection with the lever II8, which connects it .to the accelerator, and up into the small motor cylinder I21 where it carries a piston I28. The top of the motor cylinder I21 cylinder I28 may be connected to a. source of vacuum. When this is done, it is obvious that the piston I20, valve stem )4 and the valve piston I05 will be raised to their upper position or, if they are already in that position they will be held there with the valve piston I05 firmly seated against the upper valve seat I02. As may be seen from Figure l, the lost motion connection I2I is arranged so that the master valve 29 may thus be held in open position by vacuum in the cylinder I21 irrespective of the position of the throttle 3|. As will be explained below, the cylinder I21 is employedonly for holding the master valve 29 in open position and not for causing it to open. Thus the master valve 29 is opened only by the release of pressure upon the accelerator pedal 3| but may, under certain conditions, be held in open position even though the accelerator pedal 3| is again depressed.

Master valve and shifter interlock The small motor cylinder I 21 on the master valve 29 is employed only as part of an interlock mechanism for holding the master valve open during the progress of a shift. This is done in order to keep the shifting mechanism operating until a shift is completed so that a premature depression of the accelerator pedal 3| will not.

ends of the path of the slide 39. The two levers I3I and I32 are connected together by a link I33 so that they will swing in opposite directions, that is, when one lever I3I swings away from the center of the shifter toward the, rear of the shifter the other lever I32 will also swing away from the center of the shifter and toward the front of the shifter.

The linkage formed by the two levers I3I and I32 and .the link I33 is connected to the stem I34 of an interlock valve I35 mounted on the frame of the shifter. The interlock valve I35, shown diagrammatically in Figure 1, is similar in its interior construction to the main portion of the master valve 29 shown in detail in Figure 9, except that it is not provided with a spring in its interior, tending to pull the valve stem into the valve. Instead a spring I36 is connected. to the linkage I3I, I32, I33 which operates the valve,

stem I34 in such a way as to tend to pull the valve stem I34 out of the valve I35 and to close'the atmospheric-vent of the valve through which the valve stem I34 extends.

' The interlock valve I35 is provided with two connections, one leading to a port in the side of the valve cylinder and the other leading to an aperture in the valve seat at the end of the valve opposite the end through which the valve stem I34 extends. The latter connection |31 leads to themain vacuum supply line 4 so that when the two levers I32 and I3I are swungtogether by the spring I36, the valve stem I34 will be pulled out, causing the atmospheric vent to be sealed and placing theinterior of the valve I35 in direct communication with the source of vacuum. w

. The conduit I29 leading from the port in the side of the valve I35 is the conduit connected to the top of thesmall motor cylinder on the master valve 29. Thus, when the two small levers I3I and I32 on the shifter I are swung toward each other, the interlock valve I35 will allow suction from the engine manifold I I5 to be applied to the small motor cylinder of the master valve 29 and hold the master valve open irrespective of whether the throttle 3| is allowed to remain in its released position or not. i

In order-to cause the master valve 29 to be held open at the proper time, the laterally slidable outer shell 53, 54'on the slide 39 of the shifter is provided on its upper surface with a pair of upwardly projecting pins I39 and I39 which are placed so as to engage lugs I41, I42, I43, I44 on the levers I3I and I32. The pins I39 and I39 carried by the laterally slidable outer shell 53, 54 of the shifter are placed so that one pin I39 engages the lugs I41, I43 on one lever I3I, and the other pin I39 engages the lugs I42 and I44 on the other lever I32. Thus a different one of the four lugs, I4I, I42, I43 and I44 is engaged upon the completion of each shift. Thus each lug can be Hand operated control valve In order that the operator of the motor vehicle may be able to choose whether the vehicle shall move forward or backward or remain stationary with the engine running, a hand operated control valve 24 is provided. This valve is located or reverse" position. When the valve 24 is inv in any convenient location, such as on the instrument board, and may be placed in three positions. In one position, the one in which it is shown in Figure l and, in full lines in Figure 6,

it forms the proper connections so that the trans-' mission controlled mechanism will cause the vehicle to move in a forward direction. In another position, the one shown in dotted lines in Figure 6, it forms-the connections which will cause the vehicle to move in a reverse direction. In an intermediate position, which serves as a neutral, the vehicle will move in neither direction. The valve 24 may be of any one of several difierent types but, for the sake of convenience in illustration, it [has been shown as a simple rotary valve somewhat similar to a common stopcock. The central portion of the valve is rotatable and contains two sets of passages which function entirely independently of each other. One set of passages I41 and I49 is T-shaped in plan and serves to connect the vacuum conduit I49 from the master a conduit I59 leading to the small motor cylinder I 51 for withdrawing the latch I54. The W-shaped passages I53 are arranged so that when the valve 24 is in its intermediate or neutral position, the conduit I58 which supplies vacuum is cut on and the conduit I59 from the latch motor I5! is connected to a vent I-6I, thus deenergizing the motor I51 and allowing the spring I56 to move the latch I54 into engagement so that it will hold down the clutch until the hand operated valve .24 is moved to either its ahead or reverse position. It may bepointed out that the control for the latch I54 is arranged so that the latch will remain in engagement after the motor I I6 is stopped and its intake manifold II5 ceases to be a source of vacuum.

Automatic selector valve The automatic selector valve 25 is what determines which of the three forward speeds are to be engaged by the shifter I5. This valve may obviously be of many different forms such as a piston valve, rotary valve, or a plurality of poppet valves operated by cams or other means, but it has been shown, for the sake of simplicity, as a simple rotary valve, somewhat, similar to an ordinary stopcock. I

The rotary portion of the automatic selector valve 25 contains a three branched passageway I62 by means of which the "ahead vacuum conduit I5I can be connected to the low speed vacuum conduit I63, the intermediate speed vacuum valve 29 to either the reverse vacuum conduit 91 or to the ahea vacuum conduit I5I leading to the automatic selector valve 25, depending upon whether the hand valve 24 is in the ahead the neutral position, neither the ahead" vacuum conduit I5I nor the "reverse vacuum conduit 91 is connected to the vacuum conduit I49 but both are connected to the atmosphere through a vent I52.

The other set of passages I53 in the valve 24 are somewhat similar to a W in plan, and serve to control a latch I 54 for the clutch pedal 'II.

' The latch I54 is placed so as to engage a detent conduit I64 or the high speed vacuum conduit I65. The. three branched passage I 62 and the ports leading to the ahead vacuum conduit and to the low, intermediate and high vacuum conduits are placed so that the low, intermediate and high vacuum conduits, are successively placed in communication with the "ahead" vacuum conduit I5I as the valve 25 is rotated.

As may be seen in Figure 5, the ports of the, various vacuum conduits leading to the valve 25 are arranged so that there is an appreciable angle between the position of the valve in which the ahead vacuum conduit is connected to one of the three speed conduits I63, I64 and I65 and the position in which it is connected to the next one of the three speed conduits I63, I64 and I65. When the valve is in one of these intermediate positions, the three-branch passage I 62 in the rotary part of the valve is still connected to one of the three forward speed vacuum conduits I63, I64, I65 through one of its branches which has an enlarged and and another of its branches is connected to ports leadingto a vent I66. Thus, as the valve 25 is rotated from its low speed position, shown in full lines in Figure 5, the low speed vacuum conduit I63 is disconnected from the ahead vacuum conduit I5I and is connected to the vent I66 as shown by dotted lines in Figure 5. This allows atmospheric pressure to reach the upper end of the cylinder of the low speed relay valve I9 and permits the spring I6'I to move into its 03" posltion'irrespective'of whether the master'valve 29 is open or not. In a similar manner, the intermediate speed vacuum conduit I64 and the high speed vacuum conduit I65 are connected to the vent I66 when the valve 25 is at either side of the positions in which they are connected-to ahead vacuum conduit II. Thus, in every case, after a shift has been made and the selector valve 25 is moved toward a position to cause another shift to be made, the relay valve I9, 20 or M which was involved in the completed shift is vented to atmosphere and allowed to return to its ofi" position.

Therotor of the automatic selector valve 25 is provided with an arm I68 by means of which it is moved from one position to another. The arm I68 is connected by a link I69 to a speed responsive mechanism which operates the valve 25 and which will be described in detail below.

Automatic clutch control Although-the clutch I1 may be depressed when desired by the foot of theoperator of the motor vehicle, the invention, in its preferred form, includes a mechanism for automatically depressing the clutch pedal I1 and thereby disengaging the clutch whenever the operator completely releases the accelerator pedal 3I. This mechanism comprises a vacuum motor cylinder I12 containing a piston I13 which is connected by means of a piston rod I14 and a link H15 to the clutch pedal I1. Thus, whenever the cylinder I12 is connected to a source of vacuum, the piston I13 will be drawn into the cylinder and the clutch will be disengaged. The connection of the cylinder I12 to the intake manifold II5 of the engine II6, which is the source of vacuum, is accomplished through a clutch relay valve 28 and the master valve 29, and the rate at which air is allowed to reenter the cylinder I12 after the vacuum is cut off is determined by a clutch engagement control 38, all of which will be described in greater detail be- Clutch relay valve and clutch engagement control The clutch relay valve 28 and the clutch engagement control 38 are preferably formed in a single unit as shown in detail in Figure 8.' The clutch relay valve 28 comprises a cylinder I11 having valve seats I18 and I19. The two valve seats I18 and I19 are formed with upstanding circular walls and central apertures and cooperate with a piston I8I in the valve cylinder I11'in the same way as the similar parts of the master valve 29 shown in Figure 9. The aperture in the upper valve seat I18 is connected to the vacuum conduit I49 leading from the master valve 29 and the aperture in the lower valve seat I19 is connected 5 to a vent I82 in the clutch engagement control 38. Thus, when the piston I 8| is in its lower position and the master valve 29 is open, the

space within the cylinder I11 will be connected 'through'the conduits I49 and 4 to the intake manifold II5 which is the source vof vacuum.

When the piston I8I is in its'upper position against the seat I16, the vacuum will be cut off and the space within the cylinder I11 will be filled with air at atmospheric pressure reaching it through the vent I82. -The cylinder I11 is provided with a port I83 in its side which is'connected by a conduit I84 to the clutch motor cyltends out to it small vacuum motor cylinder I86;

The cylinder I86 contains a piston I81 secured to the valve rod or stem I85 and a spring I88 under the piston I81 and urging it upward.

Vacuum is admitted to the cylinder I86 through a conduit I89 which is connected to the vacuum conduit I49 from the mastervalve 29 through a clutch lockout valve 32. Thus, when the lockout valve 32 is open, the cylinder I86 will be connected to the source oi vacuum I I5 whenever the master valve is opened, and the .valve piston I8I of the clutch relay valve 28 will move practically in synchronism with the master valve 29. This will cause the clutch pedal I1 to be depressed whenever the accelerator'pedal 3I is entirely re- V leased, excepting when the clutch lockout valve 32 is closed. The construction and function of the clutch lockout valve 32 will be described in detail below.

The clutch engagement control 30, which is formed in a unit with the clutch relay valve 28 and which is illustrated in detail in Figure 8, comprises a cylinder I9I into one side of which opens the circuit I92 leading from the aperture in the lower valve seat I19 of the clutch relay valve 28. The wall of the cylinder I9] contains a port or vent I82 which is ofiset longitudinally of the cylinder from the end of the conduit I92. The vent I82 is partially closed by a piston I93 which is slidable within the cylinder I9I and which is fixed to a piston rod I94 extending out through both ends of the cylinder I9I. A pair of slightly larger cylinders I95 and I96 are carried,

one at each end of the cylinder I9I and contain pistons I91 and I98 secured to the ends of the piston rod I94. The outer ends 26!, 202 of the two cylinders I95 and I96 carry setscrews 203, 284 which project into the cylinders-I95 and I96 and form stops against which the ends of the piston rod I94 may abut. Thus the possible range of movement of the piston and piston rod assembly I93, I94, I91, I98, may be accurately adjusted for the purpose of controlling the range of movement of the piston I93. The piston I93 partly covers the'port I82 which serves as the vent through which the cylinder I12, which operates the clutch pedal I1, receives air at atmospheric pressure. vThus the position'of the piston I93 determines the size of the vent I82 and will therefore determine the rate at which theclutch pedal I1 rises and the clutch engages.

Two positions are provided for the piston I93 in order to provide two different rates of clutch engagement.

In order to give a slower rate of clutch engagement when the gear box is in low or reverse, the left-hand end of one vacuum cylinder I96 is connected by means of a conduit 205 to the low speed vacuum conduit I63 and-the left-hand end of the other vacuum cylinder I95 is connected by means of another conduit 266 to the reverse vacuum conduit 91. Similarly the right-hand ends of the two vacuum cylinders I 95 and I96 are connected by conduits 261 and 268 to the in-- termediate speed and high speed vacuum conduits I64 and I65. Thus, as soon as the hand control.

valve 24 or the automatic selector valve 25 is set to give a shift into any particular speed and vacuum is admitted to. operate the proper relay valve I8, I9, 29. or 2|, vacuum will also be admitted to one end or the other of one or the other of the two cylinders I95 and I96 and the piston I93 controlling the clutch rate of engagement vent I82 will be moved into the position correspending with the speed for which the. transmission mechanism is set.

operated pump I6.

Clutch lockout valve The clutch lockout valve 32 is similar in its general construction to the automatic control valve 25 and is arranged to be operated simultaneously with it. If desired, the two valves may be operated by a single shaft or they may be constructed as a Single unit, but, for the purpose of illustration, they are shown in the drawings as two separate valves side by side, and the clutch lockou't valve 32 is provided with an arm 209 connected by a link 2 to the similar arm I68 on the automatic control valve 25. Thus the two valves will rotate together. The clutch lockout valve 32 is connected by a conduit I89 to the cylinder I86 and by conduits 2I2, 2I3 and I49 to the master valve 29 and is provided with a threebranch passage 2I4 for connecting the conduits I89 and 2l2 together.

As may be seen from Figure 7, the ports with which the three-branch passage 2 I4 in the rotary part of the valve 32 cooperate are placed so that the conduit I89 is connected to the conduit 2I2 and the clutch relay valve motor cylinder I86 is connected to the master valve 29 only when the lockout valve 32 is in certain positions. These positions are arranged so that the communication is established only when the automatic see lector valve 25 is in one of the three positions corresponding to the three forward speeds, namely, low, intermediate and high. It may also be noted that one branch of the passage 2 in the rotary element of the valve 32 communicates with ports leading to a vent 2 I 5 whenever the valve 32 is not in a position corresponding to one of the three speeds. For example, when the valve 32 is turned from its low speed position and is half way be tween its low speed position and its intermediate speed position, the three-branch passage 2 I 4 will be in the position shown by the dottedlines in Figure 7, and the conduit I89 will be connected to the vent 2I5, and wi l not be connected to the conduit 2I2 leading to the master valve 29. In a similar manner, asimilar connection is made when the valve 32 is between its intermediate and high speed positions or when it is moved beyond its high speed position. v

The provision for disconnecting the conduit I89 through which the clutch relay valve 28 is operated and the conduit 2I2 leading to .the master valve 29 when the valve 32 is moved to a position beyond its high speed position is especially important because it prevents the unnecessary disengagement of the clutch each time the accelerator 3I is released when the gear box is in high speed and-the-vehicle-speed is such that no shift is to be made.

The clutch lockout valve 32 is moved to the position beyond third speed by the same mechanism which moves it and the automatic selector valve 25 to the positions corresponding to low, intermediate and high speeds. .This mechanism will be described in detail below.

Shifter actuating value As has been explained above, the speed of the gear box-which will be placed in engagement by the shifter I5 is determined by the operation of the hand control valve 24, the automatic selector valve 25 and the relay valves I8, I9, and 2I, and the time at which any selected shift is made is determined by the operation of the vacuum. The pump I6, in turn,- is controlled by a shifter actuating valve 2". The shifter. actuating valve 2, shown diagrammatically in Figure 1, just below the clutch pedal I1, is similar in its construction to the master valve 29 which is shown in detail in Figure 9, but it is not provided with a small motor cylinder similar to the cylinder I21 associated with the master valve 29. The valve stem 2I8 of the shifter actuating valve 2 I1 is connected to a lever 2I9 which is pivoted so that one end is closely adjacent the piston rod I14 through which the clutch pedal I1 is depressed. The piston rod I14 is provided with a laterally extending lug 22I placed so as to engage the end of the lever 2I9 at the end of the downward movement of v the clutch pedal IT. This moves the lever 2I9 and lifts the valve stem 2I8 and moves the piston 222 of the shifter actuating valve 2II from its lower to its upper position. This opens the valve 2II and places the conduit'86 leading to the vacuum motor cylinder of the pumpv I8 in communication with the conduit 223 leading to the intakemanifold II5 which serves as a source of suction. Thus, whenever the clutch pedal I1 is depressed and the clutch disengaged, vacuum will be applied to the cylinder 82 of the pump unit and the oil or other hydraulic liquid in'the pump cylinder 8| and in the oil pressure conduit 93 will be placed under pressure. A shift will then be made if one of the relay valves I8, I9, 20, or 2I is in its upper position, but no shift will be made nor will any movement of the pump I6 take place if the various control valves are .not in such a position as to cause one of the relay valves to be actuated.

General operation of control valves, clutch operating mechanism and shifter Before proceeding to a description of the governor mechanism which determines the position of the automatic control valve 25 and the clutch lockout valve 32, it may be well to recapitulate the operation of that portion of the system which has been thus far described.

The hand valve 24 and the automatic selector valve 25 together determine which speed, if any,

of the gear box is to be placed in engagement. The hand valve 24 may be in neutral position in which case vacuum cannot reach any of the selector valves I 8, I9, 20 or 2I and no shifts can take place. When the hand valve is in this position, the clutch latch I54 is in a positiorr to hold the clutch pedal I! in its depressed position and hold the clutch out of engagement. This provides for a neutral position. When the hand valve 24 is moved in either direction from its neutral position to either its ahead or its reverse position, the latch I54 is withdrawn by the admission of vacuum to the cylinder I51. Assuming that the engine H6 is idling and the accelerator pedal 3| is in its elevated or released position, the master valve 29 will be open and vacuum will be applied to the actuating cylinder I86 of the clutch relay valve and, through the clutch relay valve 28 to the clutch vacuum motor cylinder I12, thus holdingthe clutch pedal I! in its depressed position even though the latch I54 is released.

If, at this time, the vehicle is at rest ashas been assumed, the automatic selector valve 25 will be in the position shown in Figure 1.. Therefore, depending upon whether the hand actuated valve 24 was turned to its ahead or reverse position either the low speed relay valve I9 or the reverse speed relay valve I8 will be actuated. .As soon as this happens, the oil pressure duct 93 is placed in communication with either the low speed oil line 56 or the reverse speed 011 line 55. At this time, since the clutch I1 is being held in its depressed position, the shifter actuating valve 211 will be opened and the pump cylinder 82 will be in communication with the source of vacum through it, and the oil in the oil pressure line 93 will be under pressure. Therefore, the shifter I 5 will operate to engage the gear ratio selected unless that gear ratio happens'to be already in engagement, in which case no further movement of the shifter l5 can take place.

When the throttle or accelerator pedal 3! is depressed, the master valve 29 closes. This cuts oil" the vacuum from the motor cylinder I83 of the clutch relay valve 29 which thereupon closes the vacuum connection I49 and opens the passage to the vent l82, thus allowing the clutch pedal I! to rise and the clutch to come into engagement. The rate of engagement is determined by the clutch engagement control 30 which has already been placed in the position corresponding to the speed selected, this having been done through its connections through the vacuum conduit'leading to the four relay valves 88, i9, 29 and 2!. I

As soon as the clutch pedal il rises, the shifter actuating valve 281 is allowed to close, cutting off the vacuum from the cylinder 82 which operates the oil pump. This allows the weight 88 on the oil pump motor piston 85 to pull the motor piston 85 and the pump piston 63 down to their lower positions, filling-the pump cylinder tl with oil from the reservoir 89. The system is then valve 25 has reached the position corresponding ready to perform another shift.

Another shift, is not made until two things take place, the moving of the manually operthe clutch control mechanism will operate, de-

pressing the clutch pedal H, but no shifting will take place. If the master valve 29 is opened after the automatic selector valve 25 has been moved from the position corresponding to the speed in engagement but has not been moved far enough to reach the position corresponding to the next speed, the opening of the master valve will have no effect whatever. In these circumstances the clutch lockout valve'32 will be in an off position and will prevent suction from reaching theoperating cylinder I86 of the clutch relay valve 28, thus preventing operation of the clutch and opening of the shifter actuator valve 2.

If the automatic selector valve 25, for example, reaches the position corresponding to second speed without the master valve 29 being opened, nothing will take place because the vacuum for operating the clutch motor I I! will be cut off both at the master valve 29 and at the clutch relay valve 28.

When, for example, the vehicle has been accelerated in low speed and the automatic selector to second speed and the operator of the motor vehicle'desires to shift intov second speed, he re- -leases his foot from the accelerator pedal 3|, 9.1- lowing it to rise completely. This causes vacuum to be admitted to operate the intermediate speed relay valve 20 and to. operate the clutch by the spring 231'.

automatic selector valve 25 and the operation of the master valve 29".

Governor mechanism The automatic selector valve 25 and the clutch lockout valve 32 are operated by a governor 26 through a ratchet and pawl mechanism 21 and a link I69. The governor 23 is of the centrifugal type and consists of a pair of flyweights 225 carried by a verticalshaft 226. The shaft 226 is arranged to be driven by any suitable mechanism at a speed which is proportional to the speed of the vehicle. The flyweights 225 are connected to a non-rotating collar 221 on the governor shaft 228 so that, as they rotate and are moved outward by centrifugal force, they lift the collar 22]. Upward movement of the collar 22! is opposed by a weight 228 which is connected to it by a rod 229. A second weight 23! is supported on a rest 232 and is arranged to be picked up by the weight 228 on the rod 229 as the rod 229 rises. Thus the weight 229, which is the only weight which acts on the governor at low speed, can be made lighter than otherwise, thus making the governor more sensitive at low speed.

The collar 221 of the governor 26 is connected to a ratchet plate 233 by a link 234 so that the ratchet plate 233 will swing about a central pivot 235 as the governor weights 225 and the collar 22! rise. The ratchet plate 233, in turn, is connected to the link I69 which actuates the automatic selector valve 25 and the clutch lockout valve 32. Adjacent one edge of the ratchet plate 233 is a pawl carrier 235 which is carried on .a pivot236 or other means which will allow it to move toward or away from the ratchet plate 233. A spring 23'! urges the pawl carrier 235 ;toward the ratchet plate 233 and a stop 238 prevents it from moving closer than a certain predetermined distance.

Mounted on the pawl carrier 235 are two pivoted pawls 239 and 24! spaced a short distance apart-and extending toward the ratchet plate 233. The two pawls 239 and 2 are urged in oppositedirections by a spring 242 and are prevented from moving past their operative positions under the influence of the spring 242 by a pair of stops 243 and 244 carried by the pawl carrier 235;

The ratchet plate 233 is provided with three detents or teeth 244, 245 and 246 which project out so as to engage the pawls 239 and 2 when the pawl carrier 235 is held against its stop 238 Two'of the detents 244 and 245 are placed on the ratchet plate 233 in such a position as to engage the two pawls 239 and 2 when the ratchet plate 233 is exactly in the position corresponding to intermediate speed, that is, to the intermediate speed position of the automatic selector valve 25.

Since one pawl 239 is prevented by its stop 243 pawl 24! is prevented by its stop 244 from swinging in the other direction, one or the other of the two detents-244 and 245 will come up against apawl 239 or 24! which will not swing out of its way when the ratchet plate 233 reaches the intermediate or second speed position, no matter whether this position is reached from a movement up from slow or first speed position or a movement down from third or high speed position. For example, in Figure 2, the ratchet plate 233 is shown in the low or first speed position and in Figure 3 it is shown after having moved to second or intermediate speed position, and further movement is prevented by the detent 245 which has come up against the pawl 2. v The pawl 24I cannot swing out of the way because it is restrained vby the stop 244. The other pawl 239 has been pushed aside against the tension of the spring 242 and thus is not operative in this position.

Figure 2 represents the position of the governor 26 and ratchet and pawl mechanism 21 when the vehicle is at rest. When the ratchet plate 233 is in the position shown in this figurefthe selector valve 25 is in low speed position.

when the vehicle starts, it starts out in low speed. As the vehicle speeds up, the governor weights 225 rise and swing the ratchet plate 233 toward the position shown in Figure 3. When the ratch- 25 et plate 233 reaches the position shown in Figure 3, the selector valve 25 is in its intermediate speed position, and ashift to intermediate speed P sition will be made if the accelerator petal-3i is fully released.

If, after the ratchet plate 233 reaches the intermediate speed position shown in Figure 3,

the operator of the vehicle continues to accelerate and keeps the accelerator pedal 3| depressed,

no shift will take place and the vehicle will continue to accelerate in low or first speed. It may gear will take place when the accelerator pedal- 3| is released. This prevents shifts from being made from low gear directly into high gear without going through intermediate'gear.

When a shift from low gear to intermediate gear takes place, it is necessary to release the ratchet plate, 233 so thatit may move on to high gear position. This is accomplished by a small vacuum cylinder 255 which is connected to the source of vacuum 5 through a conduit 2l3 and the master valve 23. The cylinder 255 contains a piston 243,0n the end of a piston rod 241 and a spring 253 acting to normally retract the piston rod 241. The vacuum conduit 2 is connectedsoas to cause the piston rod 241 to move out of the cylinder 245 when vacuum is applied.

7 do The end of the-piston rod 241 is formed into a hook 248 which is adapted to engage a hook shaped pawl 243 pivotally mounted upon the pawl carrier 23!. The hook shaped pawl 249 is normally held in a position to be engaged by the 35 hook 243 on e piston'rod 241 by. spring I and is prevented from moving beyond that position b a stop 252.; Thus, whenever the master I I valve 23 is open to allow a shift to be made, vacuum will be applied through the conduit 3 to the cylinder 24l and the hook end 243 of the-pis ton' rod 241 will move forward andengwe th hook end of-the pawl 243 as shownin'Flgur-e 3. After. shift is completed and the master valve :0 closes, cutting on the conduit :1: fromthe 15 source of suction III, the spring 253 will retract Therefore,

third gear.

- broadest sense as including both the clutch and the piston rod 241, pulling back with it the hook shaped pawl 243 and the entire pawl carrier 235, to the position shown in Figure 4. This movement withdraws the pawl 2" from engagement with the detent 244'on the ratchet plate 233 and 5 allows the ratchet plate 233 to move on past its intermediate speed position as shown in Figure 4. However, as soon as this movement occurs, the hook shaped pawl 243 is swimg out of engagement with the hook shaped end of the piston rod 10 241 by a disengaging pin 253-against which a cam surface on the hook shaped pawl 243 comes into contact as the hook shaped pawl 249 is pulled back by the piston rod-241. This action is shown in Figure 4, and as soon as the disengagement is completed, the pawl carrier 235 is swung back to its original position, shown dotted in Figure 4, by means of the spring 231.

When the pawl carrier 235 returns to the position shown in dotted lines in Figure 4, the 20 ratchet plate 233 has moved past the intermediate speed position to approximately the position shown in Figure 4 and the pawl 2 which formerly engaged the detent 245 and prevented I movement of the ratchet plate 233 now swings 25 in out of engagement with the detent 245. Thus the ratchet plate 233 is free to move to its high or third speed position under the influence of the governor 25.

Movement of the ratchet plate 233 past the 30 third speed position while the gear box is still 7 in second gear is prevented by the third detent 246 which engages the pawl 2 in the same manner as the second detent 245 engaged the pawl 2" as shown in Figure 3. Thus the ratchet 35 plate 233 is prevented from going beyond its third speed position until a shift into third speed is made in exactly the same way as it was prevented from going beyond its second speed position until a shiftinto second speed was made. When the shift into third speed is inade, the ratchet plate 233 is released to move beyond third speed position by the action of the cylinder 255 in the same way as it was released to move beyond second speed position when a shift into second was made. This moves the clutch lockout valve 32 into its beyond third speed position and prevents unnecessary operation of the vclutch after the gear box has been placed in r Movement of the ratchet plate 233 in this direction is limited by a suitable'stop 255. In shifting down from third speed to first speed, a similar action takes place, the detent 244 cooperating with the pawl 233 in the same way as the detent 245 cooperated with the pawl 2 in shifting up from first speed through second speed into third speed. This insures that second speed will not be omitted and an attempt made to shift directly from high gear into low Bear.

From the-above description and the accompanying drawings, it will be seen that I have provided an. automatic transmission control mechanism, using the word transmission" in its seen .that my automatic transmission control 76 H v.

mechanism does. not require extensive changes in the design of automobiles or their p0Wer plants. It will also be apparent that this mechf anism can'be applied to existing cars as an ac-.

cessory or applied to cars being manufactureda separate source of vacuum being provided to operate the control mechanism.

Although I have described my automatic transmission control mechanism as being operated by 15 suction or vacuum, it will be apparent that the entire system can be constructed to operate by compressed air in place of vacuum and such an arrangement may be desirable in applying the system to vehicles, such as trucks 01' buses, hav- 20 lng compressed air for the operation of the- While I have shown one P rticular embodi- 30 ,ment or my invention and discussed a few other, possible embodiments or modifications, it will,

of course, be understood that I do not wish to be limited thereto since many pther modifications may be made, and I therefore contemplate by 35 the appended claims to cover all such modifications as fall within the true spirit and scopeof my invention.

I claim as my invention: 1. In an automatic control mechanism for a 40) motor vehicle havin g'a gear box, a selector member movable between three successive positions which correspond to three successive ratios which maybe made operative in the gear box, power means for making operative whatever gear 45 ratio corresponds to the position of the selector member, a manually operable control member for setting said power means into action, latch means for preventing the movement of said selector member past the intermediate one of said I 50 three successive positions, and means responsive to, the operation of said controlmember for re-.

leasing said latch means immediately after said operations 2. In an automatic control mechanism for a 55 motor vehicle having a gear box, a selector member movable between't'hree' successive positions which correspond. to three successive ratios which may be made operative in the gear box, power means for making operative whatever gear c ratio corresponds to the position of the selector member, a manually operable control member for setting said power means into action, latch means for preventing the movement of said selector member past the intermediate one of said 65 three successive positions, and means responsive to the making operative of a gear ratio for releasing said latch means after saidgear'ratio I is made operative.

3. In an automatic control mechanism for a 70 motor vehicle havinga clutch and a gear box, a

selector member movable between and beyon three successive positions which correspond to three successive ratios which may be made operative in the gear box, means .responsive to-the,

75 speed of the vehicle for moving said selector member through and beyond its successive positions as the speed of the vehicle increases,-power means for disengaging the clutch, power means set into action by the disengagement oi the clutch for making operative whatever ratio corresponds to the position of the selector member, a manually operable control member for putting said first power means into action, latch means for preventing the movement .of said selector member past the intermediate one of or beyond said three successive positions, means for preventing the operation of said clutch disengaging means when said selector is beyond said positions, and means responsive to the making operative of any of said ratios for momentarily l5 releasing said latch means 4. In an automatic control mechanism for a motor vehicle having a clutch and a gear box, a selector member movable between and beyond three successive positions which correspond to three successive gear ratios which may be made operative in the gear box, power means for dis engaging the clutch, power means set into action by the disengagement oi the'clutch for making operative whichever gear ratio in the gear box corresponds to the position of the selector memher, a manually operable control member for putting said first power means into action, latch means for preventing the movement of said selector member past the intermediate one or beyond one of the outer ones of said three successive positions, and means responsive to the operation of said control member for releasing said latch means.

5. In an automatic control mechanism for a motor vehicle having a clutch and a gear box, a

\ selector member movable between and beyond three successive positions which correspond to three successive gear ratios which may be made operative in the gear box, power means for disengaging the clutch, power means set into action by the disengagement of the clutch for making operative whichever gear ratio in the gear box corresponds to the position of the selector member, a manually operable control member for putting said first power means into action, latch means for preventing the movement of said selector member past the intermediate one or.

beyond one oi the outer ones of said three successive positions, means for preventing the operation of said clutch disengaging means when saidselector member is beyond said positions, and means responsive to the making operative of a gear ratio for releasing said latch means.

6. In a control mechanism for a motor ve-, hicle having an engine, a clutch, and an automatically controlled gear box, a latch for holding the clutch out of engagement, a manually operable control member, power means controlled by said control member for setting said gear box to move the vehicle ahead when said control member is in one position and for setting said gear box to move the vehicle back when said control member is in another position, and means responsive to theposition of said controlmember for releasing said latch" when said control member is ineither oi said positions and for making said latch operative when 'said control member is in neither of said positions.

7. In a motor vehicle having a clutch, a gear-'10 box and a manually operable power control member, an automatic control-mechanism comprising power means for disengaging the clutch and. changing the gear ratio or the gear box,

means responsive to the speed of the vehicle for 15 1 determining the gear ratio to be made operative,

and means for making said power means inoperative when said gear box is in direct drive and said vehicle is moving faster than a predetermined speed.

8. In an automatic control mechanism for a motor vehicle having an accelerator and a clutch and a gear box, power mechanism for disengaging said clutch, power shift mechanism operative upon disengagement of the clutch for se1ec-- tively engaging the gears in the gearbox, selector means responsive to the speed of the vehicle for determining the gears to be engaged, and means for making said clutch disengaging means inoperative when said selector means is not set to permit operation of said power shift mechanism.

9. In an automatic control mechanism for a motor vehicle having an engine and a clutch and a gear box with a plurality of ratios, a vacuum cylinder for disengaging the clutch when vacuum is applied thereto, a vent for breaking said vacuum and allowing said clutch to engage, power mechanism for making operative any one of the ratios of the gear box, selector mechanism for determiningthe ratio to be made operative, and means operated by said selector mechanism .for partially closing said vent in certain positions of said selector mechanism for providing a slower rate of, clutch engagement for said positions of said selector mechanism. 7

10. In an automatic control mechanism for a motor vehicle having an engine and a clutch and a gear box with a plurality of ratios, power mechanism for making operative anyone of the ratios of the gear box selector mechanism for determining the ratio to be made operative, a vacuum cylinder for disengaging the clutch when vacuum is applied thereto and for allowing it to engage when 26 air is admitted thereto, means for selectively connecting said cylinder to a source of vacuum or to a vent to air at atmospheric pressure, and means operated by said selector mechanism for varying the opening of said vent for'diflerent positions of said selector mechanism.

11. In an automatic transmission, a gear shift member adapted to selectively engage and move the shiftable members of a transmission, clutch disengaging mechanism preventing the application of power to said transmission, power shifting mechanism for moving said gear shift member between several predetermined positions, control means operated by said clutch disengaging mechanism for shutting ofl the power to said shifting 5'5 mechanism except when said'clutch disengaging mechanism is operative, manually operable control means for said clutch disengaging mechanism, means for holding said manually operable control means in a position to cause clutch disengagegg ment, and means for operating said holding means whenever said shift member is in none of said predetermined positions.

12. In a power gear shiiter, a gear shift mem -ber adapted to selectively engage and move the shiftable members of a tion, power means 13. In a control mechanism for a motor vehicle having an engine, a clutch, and a gear box providing a reverse gear train and at least three of forward gear trains of different ratios, fluid pressure operated means for selectively making said gear 5 trains effective, manual control means for directing fluid pressure selectively to make either said reverse gear train or one of said forward gear trains effective, means for selecting the particular forward gear train to be'made efl'ective, speed re- 10 sponsive mechanism for operating said selecting means, and means responsive to the operation of said fluid pressure operated means for positively preventing operation of said selecting means from-a position corresponding to any gear ratio to 15 a position corresponding to a non-adjacent ratio without an intervening operation of said fluid pressure operated means with said selecting means in the position corresponding to the intervening 0 ratio. P

14, In a vacuum operated power mechanism for shifting the gears of a transmission, aplurality of hydraulic motor" cylinders and pistons, a mechanical interlock for preventing simultaneous movement of certain pairs of said pistons, means 2 for operatively connecting said pistons to said gears,'a hydraulic pump cylinder and a vacuum power cylinder having pistons connected together, means for connecting said pump cylinder to selected pairs of said motor cylinders, a source 30 of vacuum, and means for placing said vacuum power cylinder in free communication with said source.

15. In a vacuum operated power mechanism for shifting the gears of a transmission, a plurality 35 of hydraulic motor cylinders and pistons, a me- ,chanical interlock for preventing simultaneous movement of certain pairs of said pistons, means for operatively connecting said pistons to said gears, a hydraulic pump cylinder and a vacuum 40 power cylinder having pistons connected together, means for connecting said pump cylinder to selected pairs of said motor cylinders, the volume displaced by the piston of said vacuum power cylinder being substantially greater than the vol- 45 ume displaced by the piston of said pump cylinder during any joint movement 'thereof, a source of vacuum, and means for placing said vacuum supplying fluid under pressure up any one of said four conduits, and a valve means associated with each cylinder end and forming -a connection between said cylinder end and the ends of the conduits associated therewith, said valve means being constructed and arranged to permit free commimication between either one of said conduit endsand said cylinder end and to' block the other or said conduit ends'in response to pressure in said one conduit. EDWABD F. mom. K 

